Motor fuel containing an octane appreciator



3,021,204 Patented Feb. 13, 1.952

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3,021,204 MUTGR FUEL CUNTG AN GiITARE APPREQIATGR Alfred Arirell, Fishlrill, N.Y., assignor to Texaco lino, New York, N .Y., a corporation of Delaware No Drawing. Filed May 8, 1959, Ser. No. 811,796

Claims. (Cl. 4463) This invention relates to a hydrocarbon fuel composition of high octane rating. More specifically, it involves finers to rely heavily on catalytic refining operations such as fluid catalytic cracking, catalytic reforming, alkylation and catalytic isomerization.

Catalytic cracking and catalytic reforming, which are the most widely used refining operations in the producof aromatics; catalytic cracking also produces a substantial amount of olefins. It is well known that olefins and aromatics, although possessing high octane ratings, have a poorer response to organo-lead compounds such as tetraethyl lead than saturated aliphatic gasoline components. Accordingly, as the aromatic and olefinic content of the gasolines have increased to meet the octane levels required by modern automotive high compression engines, the lead response of the resulting fuels has diminished. Stated another way, the octane increment obtainable by the addition of an organo-lead compound decreases as the aromatic and olefin contents of the base fuel increase. The subject invention involves the discovery that the octane rating of leaded motor fuels contaming a substantial concentration of high octane comof acyl aldoximes of prescribed composition.

In a commonly-assigned copending application, Serial No. 689,466, filed October 11, 1957, by George W.

'Eckert, it is disclosed that hydrocarbyl monocarboxylic acids substantially raise the octane rating of a motor fuel containing an organo-lead anti-knock agent and a substantial concentration of high octane components which may be aromatic hydrocarbons, olefinic hydrocarbons or mixtures thereof. The subject invention involves the discovery that acyl aldoximes also have an octane appreciating action in leaded motor fuel compositions of this type.

The high octane hydrocarbon motor fuel of this invention comprises high octane components including a substantial concentration of aromatic hydrocarbons, olefinic hydrocarbons or mixtures thereof, an organo-lead anti-knock agent and an acyl aldoxime in a concentration of at least 0.1 volume percent of the motor fuel.

The action of acyl aldoximes in appreciating the octane rating of gasoline is characterized by several unusual features. in the first instance, the acyl aldoximes appear to be ineffective in raising the octane rating of gasoline unless an organo-lead anti-knock agent, normally tetraethyl lead, TEL, is a component of the gasoline mixture. The second unusual characteristic of the action of acyl formula:

aldoximes in appreciating the octane rating of gasolines 's the fact that an equivalent concentration of acyl alan organo-lead anti-knock agent is present.

Since organo-lead anti-knock agents exert their greatest the octane rating of aromatic and olefin-rich gasolines, the present invention neatly complements tetraethyl lead as an octane improver. Acyl aldoximes have their minimum effect where tetraethyl lead has its maximum efiect and exert their maximum efiect on octane values where tetraethyl lead has its minimum effect.

The novel fuel compositions of this invention have a minimum concentration of aromatic and/or olefin components of at least 10 volume percent. The aromatic and/or olefin components of the motor fuel of the invention can constitute as high as volume percent thereof nificant octane improvement.

The aromatic components of the motor fuel of the invention are generally supplied by catalytic reformingor catalytic cracking operations. Catalytic reformate is particularly high in aromatics. The olefin components of the motor fuel of the invention are derived either from thermal cracking, catalytic cracking or polymerization.

The organo-lead reagent necessary for the action of .pounds such as tetramethyl lead, tetrabutyl lead, tetraamyl lead, tetrapropyl lead, etc., possess anti-knock properties and may be used in the fuel compositions of the invention in conjunction with acyl aldoximes.

The tetraethyl lead mixtures commercially available for automotive use contain an ethylene chloride-ethylene bromide mixture as a scavenger for removing lead from the combustion chamber in the form of volatile lead bromide, the latter two reagents being present in 1.0 theory and 0.5 theory, respectively, theory denoting the stoichiometric amount required for reaction with the lead content of the tetraethyl lead.

The organo-lead reagent is present in the fuel comin aviation gasoline.

The acyl aldoximes which are effective in increasing the octane rating of aromatic and olefin-containing leaded gasoline are generally formed by acylating an aldoxime with an acyl halide or an acid anhydride, e.g. acetic anhydride. The elfective acyl aldoximes have the general H RO=NOOCR V wherein R is a furfuiyl radical or a hydrocarbyl radical containing 1-20 carbon atoms and preferably 1-12 carbon atoms, and R is a hydrocarbyl radical containing l-l8 and preferably 1-12 carbon atoms.

Examples ofeifective acyl aldoximes are the following: rebutyraldoxime acetate, also called acetyl n-butyraldoxime, isobutyraldoxime acetate, benzaldoxime acetate, furfuraldoxime acetate, n-propionaldoxime propionate, isobutyraldoxime Z-ethylhexanoate, benzaldoxime n-butyrate, tolualdoxime propionate, valeraldoxime laurate, benzaldoxime benzoate, acetaldoxime acetate, acetaldoxime propionate, acctaldoxime benzoate, acetaldoxime cyclohexanoate and furfuraldoxime benzoate.

An interesting feature of this invention is the fact that acyl ketoximes are ineffective in appreciating the octane rating of leaded gasoline. It has been theorized that the acyl aldoximes are effective octane appreciators because, under conditions existing in the internal combustion engine, they decompose to hydrocarbyl monocarboxylic acids and nitriles. Acyl ketoximes do not decompose in this manner at elevated temperature. The decomposition of acyl aldoximes is illustrated in the following equation showing the decomposition of acetaldoxime acetate to acetonitrile and acetic acid:

A CH CH=NOOCCH CHgGN CH COOH.

The acyl aldoxirnes must be present in the leaded aromatic and/ or olefin-containing compositions of the invention in a minimum concentration of 0.1 volume percent before a significant octane appreciation is realized. When the concentration of acyl aldoximes is below 0.1 volume percent, there is no noticeable octane improvement in leaded gasolines of prescribed composition. The preferred concentration of acyl aldoximes falls between 0.2 and 2.0 volume percent with maximum octane appreciation generally being obtained at concentrations between 0.5 and 1.5 volume percent. Although concentrations of acyl aldoximes as high as 5 volume percent may be employed with accompanying octane appreciation, economic considerations preclude the use of such high concentrations. In addition, it appears there is a fall-oif in octane appreciation after the concentration of acyl aldoxime exceeds about 1.5 volume percent.

In Table I there is shown the effectiveness of acyl aldoximes in raising the octane rating of a leaded fuel composition containing the prescribed aromatic and/ or olefin content. The base fuel employed in Table I had a research octane number (RON) of 105, a motor octane number (MON) of 98.5 and comprised approximately 10 volume percent nbutane, 40 percent isobutylene-isobutane alkylate, 10 percent pentenes from fluid catalytically cracked naphtha and 40 percent heavy platformate; the base fuel contained 3 cc. of TEL per gallon. Fluorescent indicator analysis (FIA) of the 105 octane base fuel indicated an aromatic content of approximately '55 percent and an olefin content of approximately 6 percent; its initial boiling point (IBP) was 90 F. and its endpoint was 367 F.

TABLE I Units improvement in octane rating by acyl aldoximes in 105 octane fuel Xm'ts improvement in octane rating by acyl aldo)tmes in. 105 octane fuel Base Fuel+0.5 v. percent n-butyraldoximc acetate Base Fuel-H v. percent n-butyraldoximc acetgtte c a e.

ate Base Fuel-{ v. percent benzaldoxime acetate Fuel +1.0 v. percent benzaldoxinle acetate Base Fuel-i025 v. percent iurfuraldoximc acetate. Base Fnel+0.5 v. percent turfuraldoxime acetate Base Fuel-{4.0 v. percent iurfuraldoximc acetate The data in the above table clearly prove the octane appreciating action of acyl aldoximes in a leaded fuel containing the prescribed aromatic and/or olefin content.

In Table ll there is shown the octane appreciating ac tion of isobutyraldoxime acetate in a commercial premium motor fuel having an RON of 100.9. The premium motor fuel employed in Table ll contained 3 cc. of TEL per gallon and had an TB? of 89 F. and an end pointof 372 F. FlA indicated that it comprised approximately 50% saturated hydrocarbons, 30% aromatics and 20% olefinic hydrocarbons.

TABLE 11 Units improvement in octane rating of premium fuel by acyl aldoximcs RON Base fuel+0.2% isobutyraldoxime acetate 0.4 Base fuel+0.3% isobutyraldoxime acetate 0.7 Base fuel+0.4% isobutyraldoxime acetate 0.9 Base fuel+0.5% isobutyraldoxime acetate 1.4

TABLE III ineffectiveness of acyl ketoximes as octane appreciators Change in RON Base fuel+0.5 v. percent acetyl acetoxime 2.1 Base fuel+ 1.0 v. percent acetyl acetoxime -3.7

Base fuel+0.5 v. percent acetyl cyclohexanoneoxime -1.4

Base fuel+l.0 v. percent acetyl cyclohexanoneoxime 3.4

Base fuel+0.5 v. percent acetyl acetophenoneoxime l.0 Base fuel+l.0 v. percent acetyl acetophenoneoxime -1.2

In contrast with the substantial octane appreciation obtained with acyl aldoximcs, the data in Table lll shows that acyl ketoximes actually have an octane depreciating efiect on leaded fuels. The decrease in RON resulting from the addition of 0.5 to 1.0 v. percent acetyl acetoximc, acetyl cyclohexanoneoxime and acetyl acetophenoneoxime are of such magnitude that their presence could not be tolerated in a high octane motor fuel.

Obviously, many modifications and variations of the invention as hercinbefore set forth may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A hydrocarbon fuel in the gasoline boiling range containing an organo-lead anti-knock agent, at least 10 volume percent high octane components selected from the group consisting of olefinic hydrocarbons, aromatic hydrocarbons and mixtures thereof and an acyl aldoxime in a minimum concentration of 0.1 to 5.0 volume percent, said concentration being sufiicient to effect substantial octane appreciation of said fuel, said acyl aldoxime having the general formula: RCH=NOOCR wherein R is selected from the group consisting of the furfuryl radical and a hydrocarbyl radical containing 1-20 carbon atoms, and R is a hydrocarbyl radical containing 1-18.

2. The hydrocarbon fuel according to claim 1 in which said organo-lead anti-knock agent is present in a concentration between 0.5 and 4.6 cc. per gallon.

3. A hydrocarbon fuel in the gasoline boi ing range containing a tetraalkyl lead anti-knock agent in a concentration of at least 0.5 cc./gal., high octane components selected from the group consisting of olefinic hydrocar- RCH=NOOCR wherein R is selected from the group consisting of the furfuryl radical and a hydrocarbyl radical containing 1-20 carbon atoms and R is a hydrocarbyl radical containing 1-18, said acyl aldoxime being between 0.1 and 5.0 volume containing fuel is effected.

4. The hydrocarbon fuel according to claim 3 in which the concentration of said acyl aldoxime is between 0.2 and 2.0 volume percent.

5. The hydrocarbon fuel according to claim 3 in which said high octane components constitute 20-80 volume percent of said fuel.

6. The hydrocarbon fuel according to claim 3 containing 1.0 to 4.6 cc./ gal. of tetraalkyl lead.

7. The hydrocarbon fuel according to claim 3 in which said acyl aldoxime is n-butyraldoxime acetate.

8. The hydrocarbon fuel according to claim 3 in which said acyl aldoxime is isobutyraldoxime acetate.

9. The hydrocarbon fuel according to claim 3 in which said acyl aldoxime is benzaldoxime acetate.

10. The hydrocarbon fuel according to claim 3 in which said acyl aldoxirnc is furfuraldoxime acetate.

References Cited in the file of this patent UNITED STATES PATENTS 1,692,784 Orel Nov. 20, 1928 1,883,593 Cross Oct. 18, 1932 2,135,327 Conquest Nov. 1, 1938 2,280,474 Byrkit et al. Apr. 21, 1942 2,360,585 Ross et al. Oct. 17, 1944 FOREIGN PATENTS 640,311 France Mar. 26, 1928 793,967 France Dec. 2, 1935 OTHER REFERENCES 

1. A HYDROCARBON FUEL IN THE GASOLINE BOILING RANGE CONTAINING AN ORGANO-LEAD ANIT-KNOCK AGENT, AT LEAST 10 VOLUME PERCENT HIGH OCTANE COMPONENTS SELECTED FROM THE GROUP CONSISTING OF OLEFINIC HUDROCARBONS, AROMATIC HYDROCARBONS AND MIXTURES THEREOF AND AN ACYL ALDOXIME IN A MINIMUM CONCENTRATION OF 0.1 TO 5.0 VOLUME PERCENT, SAID CONCENTRAION BEING SUFFICIENT TO EFFECT SUBSTANTIAL OCTANE APPRECIATION OF SAID FUEL, SAID ACYL ADLOXIME HAVING THE GENERAL FORMULA: RCH=NOOCR'' WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF THE FURFURYL RADICAL AND A HYDROCARBYL RADICAL CONTAINING 1-20 CARBON ATOMS, AND R'' IS A HYDROCARBYL RADICAL CONTAINING 1-18. 